Making compost


This is simply tapping into the natural cycle of life and death - using the by products of decomposition to best effect in our gardens we are enhancing the cycle further.  Crops grown using organic manures are found to do consistently well.  The structure of the soil is improved, nutrients become naturally available to them, instead of often excessively available, as can be the case when artificial fertilisers are used (leading to the pollution of the environment and especially the waterways).  Plants receive more from a healthy soil than just the basic nutrients for growth (NPK – nitrogen, phosphorus and potassium) there are all sorts of beneficial microbes living within the soil that help protect the plant.

Composting is a natural process – it happens to all living matter eventually – organic material is broken down into useable form by insects, worms, fungi and bacteria and chemical reactions.  The process of composting on a garden scale aims to do this in a controlled way, adding the goodness that the plants take out back into the soil.  There are some rules to follow if you want to make good compost and a couple more to pay attention to if you want to make quick compost.  The hotter your compost heap, the quicker you will get compost.  The heat is generated by the activity of the micro-organisms.  The heat of your heap is governed by how you have made your heap, what you have added to it and in which proportions.

There are two main types of compostable material – nitrogen releasing, or ‘green’ waste and carbon releasing, or  ‘brown’ waste.  These need to be added to the compost heap in roughly equal measures and also be well mixed.  If too much ‘green’ stuff is added the heap will become a stinky mush and if too much ‘brown’ stuff is put on it will take ages for the heap to rot down at all.

Green waste – grass clippings, kitchen waste (ie veg and fruit peelings), weeds, top (leafy) growth.

Brown waste – stems, woody growth, paper and card.

The other vital ingredients to the compost heap are air and water.  The heap needs to be moist, but not wet.  Water if it seems dry, but cover with an old piece of carpet or lid of some kind to prevent the heap from getting wet – this will slow down the decomposition, especially in the winter.  There needs to be sufficient air getting into the heap for the beneficial bacteria to do their work.  Too little air will result in the anaerobic bacteria taking over and making the heap into a nasty slimy mess.  This is why heaps of grass clippings with no other courser, fibrous additions become so horrible.

Speeding up the rate of decompostion

The addition of activators (substances containing bacteria that readily break down organic matter) such as manure, existing well-rotted compost, garden soil, or shop-bought activators such as  Garrota.  Regular mixing or turning over of the ingredients in your heap will also help it rot down more quickly.  This is why the ‘tumbling’ compost maker bins are able to make compost so quickly.

Shredding woody stems

Any living matter containing lignin (wood) will take a long time to break down.  Shredding woody stems and tough leaves (like holly) will help them break down more rapidly.

Making a ‘hot heap’

The trick is to add large quantities of balanced ingredients all at once – the bigger the heap the hotter it should get – moisten with water, add an activator, cover and within 3 – 6 months your compost (in theory) should be ready.

Slow heaps

Are caused by either an imbalance of materials – too many woody bits, not enough or too much water and the weather conditions.  Compost will break down more slowly during the winter months.  It is very important to keep the heap covered in cold, wet weather.

Making leaf mould

Leaves can be incorporated into the existing compost heap or, for a superior product, make a separate heap (or a perforated black plastic bag) for leaves.  It will take longer to rot down than ordinary compost (up to 2-3 years), but is lovely stuff once it does, highly prized as a component of potting compost, or as a fine grade mulch.

What you can compost

- Garden debris – prunings, tidy ups, vegetable garden waste, weeds*

- Kitchen waste – raw peelings, tea bags, egg shells

- household rubbish – cardboard, paper, loo roll, egg boxes  (not huge quantities and scrumpled up to add   

  air to the heap and give homes to insects and beneficial invertebrates)

- contents of the hoover bag

- hair, wool, cotton, nail clippings (will take a while to break down)

- wood ash (not coal ash)

- vegetarian pet waste – if sawdust is used as bedding this will take a while to compost

*Weeds can be composted in theory if your heap is hot enough to destroy the seeds or the persistant roots of perennial weeds.  I prefer to treat these separately and either burn them or let them rot in a bucket of water before adding to the heap/making fertiliser

What you can’t compost

-  cooked food and meat (will attract vermin)

-  plastic, metal, glass etc

-  man-made fibres

-  dog and cat waste as it contains dangerous pathogens

Sustainable things to do with your compost

Once your compost is ready – it has turned a nice brown colour and smells ok (of woodland, I think).  There may be fibrous pieces and bits of uncomposted matter still in it, which can be sifted out and added to the new heap.

  1. -        make potting compost.  Combine with loam and/or horticultural grit to make compost for either sowing, potting     

  2. -        on or more permanent plantings (this is what John Innes 1, 2 and 3 compost is)

-use as a mulch to conserve moisture and nutrients

-incorporate into difficult soil to improve the structure and encourage beneficial micro-organisms


These are special boxes containing brandling worms (like the sort you get from the fishing tackle shop – not garden worms).  The worms live in one part of the box and feed on kitchen scraps.  It is their waste that is the compost, which can be removed from a hatch below.  It is quite rich and is either added to your compost or used in a similar way to manure.

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